Air conditioning system and air conditioning control method

ABSTRACT

An air conditioning system of the present disclosure includes: sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; a wing that is disposed in the underfloor space under the opening and is configured to divert an air flow direction in the underfloor space by changing a slant angle of the wing; and a control device that is configured to acquire ideal values set in a plurality of the sensors, acquire actual measurement values from the plurality of sensors, calculate an average error from a difference between each of the ideal values and each of the actual measurement values, and change the slant angle of the wing to reduce the average error.

TECHNICAL FIELD

The present disclosure relates to an air conditioning system and an air conditioning control method for efficiently cooling a server or the like installed on a floor having a double floor structure in a communication station building, a data center, or the like.

BACKGROUND ART

In communication station buildings, data centers, and the like, there is always a need to reduce operating costs and to improve workability and maintainability. Thus, in order to restrict story height, to effectively utilize existing buildings, or the like, the floor of an operation area employs a double floor structure, and cables for communication, power, and the like are laid in an underfloor space of the double floor.

FIG. 1 illustrates a configuration in which cold air is distributed through an underfloor space of a double floor in a communication station building, a data center, or the like. In FIG. 1, 21 refers to an underfloor space, 22 refers to a double floor, 23 refers to a floor surface, 24 refers to an opening, 31 refers to an air conditioner, 32 refers to a server rack, 51 refers to hot air, 52 refers to cold air, 53 refers to cold air, and 54 refers to hot air. The air conditioner 31, the server rack 32, and the like are installed on the floor surface 23 of the double floor. The hot air 51 is sucked into the air conditioner 31, cooled therein, and discharged as the cold air 52 toward the underfloor space 21. The cold air 53 having passed through the underfloor space 21 is distributed, via the opening 24, to the server rack 32. The cold air 53 cools the server rack 32 and is discharged as the hot air 54. In the underfloor space 21, there exist blockages such as struts for supporting the double floor 22, communication cables, power cables and the like. As described above, the cold air 53 is blown out from right under the air conditioner 31 and flows to reach the server rack 32 while the flow thereof being obstructed by the blockages.

In a system of passing cold air into an underfloor space, a technique to further improve the air conditioning efficiency has been studied as in NPL 1 or the like.

CITATION LIST Non Patent Literature

-   NPL 1: Siddharth Bhopte, et al., “EFFECT OF UNDER FLOOR BLOCKAGES ON     DATA CENTER PERFORMANCE”, Thermal and Thermomechanical Phenomena in     Electrics Systems, 2006.

SUMMARY OF THE INVENTION Technical Problem

FIGS. 2 and 3 illustrate a cold air flow in a configuration for distributing cold air through the underfloor space of the double floor illustrated in FIG. 1. In FIGS. 2 and 3, 21 refers to the underfloor space, 22 refers to the double floor, 23 refers to the floor surface. 24 refers to the opening, 31 refers to the air conditioner, 34 refers to a blockage, 52 refers to the cold air, and 53 also refers to the cold air. In FIG. 2, the cold air 52 discharged from the air conditioner 31 does not flow uniformly into the underfloor space 21, so that a bias in air velocity is generated in the cold air from the opening 24. This phenomenon, that is, the bias in air velocity of the cold air is likely to occur noticeably due to the existence of the blockage 34 such as a cable disposed on the floor surface 23 of the double floor, as depicted in FIG. 3. As a result, a bias is generated in an air volume of the cold air that is blown up from the opening 24 toward an upper side of the double floor 22.

As a result, this makes the air volume of the cold air required for the server rack installed on the double floor 22 insufficient, so that a hotspot phenomenon occurs in which a location where a specific server holds unwanted heat is generated. As discussed above, in communication station buildings, data centers, and the like, there arises a problem of the distribution of cold air, which is not appropriately carried out in the underfloor space of the double floor.

Means for Solving the Problem

The present disclosure is intended to solve the problem described above, and is a technique in which a wing for diverting the direction of an air flow is provided in an underfloor space and the distribution of cold air is appropriately maintained by changing a slant angle of the wing.

Specifically, an air conditioning system of the present disclosure includes: sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; a wing that is disposed in the underfloor space under the opening and is configured to divert an air flow direction in the underfloor space by changing a slant angle of the wing; and a control device that is configured to acquire ideal values set in a plurality of the sensors, acquire actual measurement values from the plurality of sensors, calculate an average error from a difference between each of the ideal values and each of the actual measurement values, and change the slant angle of the wing to reduce the average error.

Specifically, an air conditioning control method of the present disclosure includes: acquiring ideal values respectively set in sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; acquiring actual measurement values from a plurality of the sensors; calculating an average error from a difference between each of the actual measurement values and each of the ideal values; and changing a slant angle of a wing in such a manner as to reduce the average error. The wing is disposed in the underfloor space under the opening and is configured to divert an air flow direction in the underfloor space by changing the slant angle of the wing.

Effects of the Invention

According to the air conditioning system or the air conditioning control method of the present disclosure, the distribution of cold air may be appropriately maintained in the underfloor space of the double floor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a configuration for distributing cold air.

FIG. 2 illustrates a cold air flow in a configuration for distributing cold air.

FIG. 3 illustrates a cold air flow in a configuration for distributing cold air.

FIG. 4 illustrates an air conditioning system.

FIG. 5 also illustrates an air conditioning system.

FIG. 6 illustrates vertical rotation of a wing.

FIG. 7 illustrates horizontal rotation of a wing.

FIG. 8 illustrates a structure of a wing.

FIG. 9 illustrates a structure of a wing.

FIG. 10 also illustrates a structure of a wing.

FIG. 11 illustrates a control flowchart of wings.

FIG. 12 illustrates candidates for changing a slant angle of vertical rotation of a wing.

FIG. 13 illustrates candidates for changing a slant angle of horizontal rotation of a wing.

FIG. 14 illustrates candidates for changing a slant angle of vertical rotation and a slant angle of horizontal rotation of a wing.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. These embodiments are just illustrative examples, and the present disclosure can be implemented in forms in which various modifications and improvements are added on the basis of knowledge of those skilled in the art. Note that constituent elements with the same reference signs in the specification and the drawings are assumed to be the same constituent elements.

An air conditioning system of the present disclosure includes: sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; a wing that is disposed in the underfloor space under the opening and is configured to divert an air flow direction in the underfloor space by changing a slant angle of the wing; and a control device that is configured to acquire ideal values set in a plurality of the sensors, acquire actual measurement values from the plurality of sensors, calculate an average error from a difference between each of the ideal values and each of the actual measurement values, and change the slant angle of the wing to reduce the average error.

The configuration of the air conditioning system of the present disclosure will be described with reference to FIGS. 4 and 5. FIGS. 4 and 5 are diagrams explaining the air conditioning system of the present disclosure. FIG. 4 is a schematic diagram of a cold air flow. FIG. 5 is a diagram explaining a flow of cold air passing through the double floor from the underfloor space of the double floor. In FIGS. 4 and 5, 11 refers to a sensor, 12 refers to a wing, 21 refers to the underfloor space, 22 refers to the double floor, 23 refers to the floor surface, 24 refers to the opening, 31 refers to the air conditioner, 33 refers to an airflow guide, 52 refers to the cold air, and 53 also refers to the cold air.

The cold air 52 is discharged from the air conditioner 31 to the underfloor space 21, and is directed to flow in a desired direction by the airflow guide 33. The wing 12 is disposed in the underfloor space 21 under the opening 24 to divert the direction of the cold air flow by changing the slant angle thereof. The cold air, the flow direction of which has been diverted by the wing 12, passes through the opening 24. Part of the cold air has its flow direction unchanged, and flows through the underfloor space 21.

Diagrams explaining vertical rotation of the wing 12 are illustrated in FIG. 6. Diagrams explaining horizontal rotation of the wing are illustrated in FIG. 7. In FIGS. 6 and 7, diagrams on the upper side are plan views when seen from a top surface direction of the double floor, and diagrams on the lower side are side views when seen from a side direction of the double floor. In FIG. 6, a variable angle direction of the wing is a vertical rotation for diverting the direction of the cold air flow in the underfloor space to a direction toward the opening. By changing the slant angle of the wing, an air volume of the cold air to be diverted to the direction toward the opening is adjusted. The slant angle of the wing is smaller in (b) of FIG. 6 than that in (a) of FIG. 6. As illustrated in (a) of FIG. 6, when the slant angle is increased, the air volume of the cold air diverted to the direction toward the opening increases. As illustrated in (b) of FIG. 6, when the slant angle is decreased, the air volume of the cold air diverted to the direction toward the opening decreases.

In FIG. 7, the variable angle direction of the wing is a horizontal rotation configured to divert the direction of the cold air flow in the underfloor space in a horizontal direction. By changing the slant angle of the wing, the direction of the flow of the cold air is adjusted in the horizontal direction. At the slant angle of the wing in (a) of FIG. 7, the flow direction of the cold air flowing through the underfloor space is diverted to the left. At the slant angle of the wing in (b) of FIG. 7, the flow direction of the cold air flowing through the underfloor space is diverted to the right.

The variable angle direction of the wing may be a direction of a combination of the vertical rotation and horizontal rotation. That is, the vertical rotation and horizontal rotation of the wing are performed simultaneously to adjust the direction of the cold air flow also in the horizontal direction while adjusting the air volume of the cold air toward the opening.

Examples of wing structures are illustrated in FIGS. 8, 9, and 10. The wing structure may be a plate-shaped structure as illustrated in FIG. 8, may be a light blocking blind-shaped structure as illustrated in FIG. 9, or may be a plate-shaped structure having holes therein as illustrated in FIG. 10. In the case of the plate shape as illustrated in FIG. 8, it is possible to efficiently divert the direction of the cold air flow. In the case of the light blocking blind shape as illustrated in FIG. 9, it is possible to save a vertical rotation space of the wing. In a case where the direction of each of blades of the light blocking blind illustrated in FIG. 9 takes a vertical direction, it is possible to apply the wing also to the horizontal rotation. In the case of the plate shape having holes therein as illustrated in FIG. 10, it is also possible for the wing to withstand the cold air flowing at a high air velocity. The wing may have a structure in which the whole wing rotates or a structure in which part of the wing moves.

As illustrated in FIGS. 4 and 5, the sensor 11 is disposed on each of the openings 24. In the opening, the cold air flows at an air velocity corresponding to the air volume of the cold air or has a temperature corresponding to the air volume thereof. Thus, the sensor 11 may be an air velocity sensor configured to detect the air velocity of the cold air passing through the opening. In a case where the sensor 11 is an air velocity sensor, the air velocity of the cold air at the opening may be appropriately adjusted. In addition, the sensor 11 may be a temperature sensor configured to detect the temperature of the cold air passing through the opening. In the case where the sensor 11 is the temperature sensor, the temperature of the cold air at the opening may be appropriately adjusted.

Next, an air conditioning control method for a cooling system will be described. A control device (not illustrated) of the air conditioning system acquires ideal values respectively set in the sensors 11 disposed on the plurality of openings 24 connecting an underfloor space of the double floor and an upper side of the double floor, acquires actual measurement values from the plurality of the sensors 11, calculates an average error from a difference between each of the actual measurement values and each of the ideal values, and changes the slant angle of the wing 12, which is disposed in the underfloor space under the opening 24 and diverts the air flow direction in the underfloor space by changing the slant angle of the wing 12, in such a manner as to reduce the average error.

The average error may be a mean absolute error in Equation (1) below.

$\begin{matrix} \left\lbrack {{Math}.1} \right\rbrack &  \\ {{MAE} = {\frac{1}{n}{\overset{n}{\sum\limits_{i = 1}}{❘{p_{i} - k_{i}}❘}}}} & (1) \end{matrix}$

When evaluation is made by the mean absolute error, the average error is calculated in such a manner that the error is small as a whole. In particular, evaluation by the mean absolute error in air conditioning control is advantageous in a point that the actual measurement value of each sensor approaches the ideal value because the adjustment is performed in such a manner as to cause the difference between the actual measurement value and the ideal value to be small as a whole on the floor.

The average error may be a root mean square error in Equation (2) below.

$\begin{matrix} \left\lbrack {{Math}.2} \right\rbrack &  \\ {{RMSE} = \sqrt{\frac{1}{n}{\overset{n}{\sum\limits_{i = 1}}\left( {p_{i} - k_{i}} \right)^{2}}}} & (2) \end{matrix}$

When evaluation is made by the root mean square error, large errors are calculated as a larger average error. In particular, evaluation by the root mean square error in the air conditioning control is effective for suppressing hotspots because the hotspots generated at specific locations on the floor are each calculated as a large difference between the actual measurement value and the ideal value.

The air conditioning control method for the air conditioning system of the present disclosure will be described in detail. FIG. 11 is a flowchart of the air conditioning control method for the air conditioning system of the present disclosure. FIG. 12 represents an example of candidates for changing the slant angle of the vertical rotation of the wing, FIG. 13 represents an example of candidates for changing the slant angle of the horizontal rotation of the wing, and FIG. 14 represents an example of candidates for changing the slant angles of the vertical rotation and horizontal rotation of the wing. In the case of FIG. 14, the vertical rotation and horizontal rotation are combined.

After start (S10), the control device acquires an ideal value that is set in each sensor. A value artificially input may be acquired as the ideal value, or the ideal value may be acquired from a previously set list. Steps from S12 to S18 are performed for n wings (LOOPn). Within LOOP, an actual measurement value is acquired from each sensor, and an average error A between the actual measurement values and the ideal values previously acquired is calculated (S13). The theoretical value and the actual measurement value are air velocities when the sensor is an air velocity sensor, or temperatures when the sensor is a temperature sensor.

The control device searches candidates for changing the slant angle of the wing on which LOOP is currently performed (S14). When the wing is able to adjust the slant angle of the vertical rotation, the control device searches candidates from a1 to ax in the table of FIG. 12 for changing the slant angle of the wing. When the wing is able to adjust the slant angle of the horizontal rotation, the control device searches candidates from b1 to by in the table of FIG. 13 for changing the slant angle of the wing. When the wing is able to adjust the slant angles of the vertical rotation and horizontal rotation, the control device searches candidates from (a1, b1) to (ax, by) in the table of FIG. 14 for changing the slant angles of the wing.

As a result of the search, in a case where there are candidates for the change (“Y” in S14), one of the candidates for changing the slant angle of the wing is selected to change the slant angle of the wing (S15). After the change of the slant angle of the wing, an actual measurement value of each sensor is acquired, and an average error B between the actual measurement values and the ideal values is calculated (S16). In a case where the average error B is not less than the average error A (“N” in S17), the changed slant angle of the wing is returned to the angle before being changed (S31). In a case where the average error B is less than the average error A (“Y” in S17), the average error A is replaced with a value of the average error B (S32).

In addition, the selected slant angle is deleted from the candidates for the change (S30). In the examples of FIGS. 12, 13, and 14, the selected slant angles are deleted from the tables. Thereafter, when there is any candidate for changing the slant angle of the wing (“Y” in S14), the same operations as those described above are repeated. When there is no candidate for changing the slant angle of the wing (“N” in S14), the slant angle adjustment of the wing is ended (S18).

Repeating the above-described operations makes it possible to set an optimal value of the slant angle for the wing.

When LOOPn has been performed on the n wings and the average error A is less than that of LOOPn−1 previously performed (“Y” in S19), the candidates for changing the slant angle of each wing are returned to the initial ones (S33), and LOOPn+1, which is the same as LOOPn, is performed again (S12). To return the candidates for the change to the initial ones means that all the slant angles having been deleted from the candidates for the change in S30 are returned. In a case where the average error A is not less than that of LOOPn−1 previously performed (“N” in S19), the slant angles of all the wings are returned to the slant angles thereof in LOOPn−1 previously performed (S20), and the control operation is ended (S21).

Repeating the above-described LOOP operation makes it possible to set an optimal value of the slant angle for each wing. As a result, the distribution of the cold air may be appropriately maintained in the underfloor space of the double floor.

A series of processing illustrated in FIG. 11 is performed when an event that may affect the air conditioning has occurred such as a case in which the situation of blockages such as cables in the underfloor space of the double floor has changed or a case in which the situation on the double floor has changed such as the amount of heat generated by the servers, the installation positions of the servers or the like, when a specified period of time has elapsed, or the like.

The control device of the present disclosure may be achieved by a computer and a program, and it is possible to record the program in a recording medium or to provide the program through a network.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied in the information communication industry.

REFERENCE SIGNS LIST

-   -   11 Sensor     -   12 Wing     -   21 Underfloor space     -   22 Double floor     -   23 Floor surface     -   24 Opening     -   31 Air conditioner     -   32 Server rack     -   33 Airflow guide     -   34 Blockage     -   51 Hot air     -   52 Cold air     -   53 Cold air     -   54 Hot air 

1. An air conditioning system, comprising: sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; a wing that is disposed in the underfloor space under the opening and is configured to divert an air flow direction in the underfloor space by changing a slant angle of the wing; and a control device that is configured to acquire ideal values set in a plurality of the sensors, acquire actual measurement values from the plurality of sensors, calculate an average error from a difference between each of the ideal values and each of the actual measurement values, and change the slant angle of the wing to reduce the average error.
 2. The air conditioning system according to claim 1, wherein a variable angle direction of the wing is a vertical rotation for diverting a direction of an air flow in the underfloor space to a direction toward the opening.
 3. The air conditioning system according to claim 1, wherein the variable angle direction of the wing is a horizontal rotation configured to divert the direction of the air flow in the underfloor space in a horizontal direction.
 4. The air conditioning system according to claim 1, wherein the sensor is an air velocity sensor.
 5. The air conditioning system according to claim 1, wherein the sensor is a temperature sensor.
 6. The air conditioning system according to claim 1 wherein the average error is a mean absolute error expressed by Equation (1): $\begin{matrix} \left\lbrack {{Math}.1} \right\rbrack &  \\ {{MAE} = {\frac{1}{n}{\overset{n}{\sum\limits_{i = 1}}{{❘{p_{i} - k_{i}}❘}.}}}} & (1) \end{matrix}$
 7. The air conditioning system according to claim 1, wherein the average error is a root mean square error expressed by Equation (2): $\begin{matrix} \left\lbrack {{Math}.2} \right\rbrack &  \\ {{RMSE} = \sqrt{\frac{1}{n}{\overset{n}{\sum\limits_{i = 1}}{\left( {p_{i} - k_{i}} \right)^{2}.}}}} & (2) \end{matrix}$
 8. An air conditioning control method, comprising: acquiring ideal values respectively set in sensors disposed on a plurality of openings connecting an underfloor space of a double floor and an upper side of the double floor; acquiring actual measurement values from a plurality of the sensors; calculating an average error from a difference between each of the actual measurement values and each of the ideal values; and changing a slant angle of a wing in such a manner as to reduce the average error, the wing being disposed in the underfloor space under the opening and being configured to divert an air flow direction in the underfloor space by changing the slant angle of the wing. 